Docs: Convert links in various docs to relative

doc/analytics/README.md

doc/analytics/contribution_analytics.md

doc/articles/how_to_configure_ldap_gitlab_ee/index.md

doc/customization/issue_and_merge_request_template.md

doc/git_hooks/git_hooks.md

doc/gitlab-basics/create-project.md

doc/install/aws/index.md

doc/install/kubernetes/index.md

doc/install/requirements.md

doc/integration/elasticsearch.md

doc/integration/saml.md

doc/integration/slash_commands.md

doc/license/README.md

doc/subscriptions/index.md

doc/update/patch_versions.md

doc/update/upgrading_from_ce_to_ee.md